1. Field of the Invention
The present invention relates to an image forming apparatus, an image forming method and a computer-readable recording medium in which a program is stored, which generates and stores a plurality of pieces of data in different formats in a common storage area in accordance with a threshold value.
2. Description of Related Art
In recent years, an image forming apparatus such as network-type copier, printer, MFP (Multi Function Peripheral) and the like became widespread. The image forming apparatus receives data in PDL (Page Description Language) format such as PS (Post Script (registered trademark)) and PCL (Printer Control Language) prepared by an external apparatus such as a PC (Personal Computer), through a network such as a LAN, once converts the received piece of data into data (intermediate data) in intermediate format and stores the intermediate data in a memory, successively reads out the intermediate data stored in the memory, converts the same into bitmap data and conduct printing.
To efficiently use a memory, Japanese Patent Application Publication Laid-open No. H10-129050 discloses, as such an image forming apparatus, a print processing apparatus which includes a plurality of input buffers each of which stores print data in band unit, a print data development processing section which develops (rasterizes) the print data into rasterized print data, a plurality of band buffers each of which stores the rasterized print data in band unit, and a work area in which one of or both of data and code required for development processing of the print data. The print processing apparatus calculates and rewrites boundary information of each area in the plurality of input buffers in accordance with amount of print data per band unit or amount of print data per page unit, calculates and rewrites boundary information of each area in the plurality of band buffers based on the image output speed determined in accordance with generating time of the print data and developing time of the print data, and rewrites the boundary information between each of the areas of the work area.
There is a technique in which there is provided a common storage area having an area (hereinafter referred to as intermediate area) which is used to generate and store intermediate data, and an area (hereinafter referred to as work area) which is used to generate bitmap data and to store the intermediate data. In this technique, data can be stored without limitation with respect to the work area in the common area, and the intermediate area is limited by providing a preset threshold value. In many cases, this preset threshold value is preset based on the memory capacity required to convert and generate intermediate data generated from PDL data with resolution and sheet size (e.g., A4 sheet) having high image forming frequency, into bitmap data, and to store the bitmap data.
There is developed an image forming apparatus which converts data in PDF (Portable Document Format) and XPS (XML Paper Specification), which are description language format of electronic document having a transparency function to allow a plurality of pieces of image data to translucently superpose to display one image, into intermediate data, and stores the intermediate data in a memory. The image forming apparatus successively reads out the intermediate data stored in the memory, converts the intermediate data into a bitmap data and conducts printing.
However, data in description language format such as the PDF and XPS having the transparency function requires a voluminous work area compared with data in description language format such as PDL having no transparency function. Even in a case where the data is a data in description language having no transparency function, a work area required when the sheet size is large or resolution is high is much larger than an area of a preset threshold value.
When the work area is larger than the preset threshold value, there is an adverse possibility that the processing is stopped until the work area is secured and there is a problem that the throughput is reduced. It may also cause a problem that the work area can not be secured, such as a case where the intermediate data is stored in the common storage area up to its capacity limitation, and there is a problem that rasterization processing to generate and store the bitmap data is stopped.
When print-data is replaced with intermediate data and rasterized data is replaced with bitmap data as in Japanese Patent Application Publication Laid-open No. H10-129050, a capacity of an area where the intermediate data is stored is changed in accordance with the data amount of the intermediate data, and a capacity of an area where the bitmap data is stored is changed based on the image output speed corresponding to the generating time of the intermediate data and to the developing time of the intermediate data. Since these areas are changed based on the intermediate data, in a case where a large volume of area to store the bitmap data is required, a similar problem occurs.